Two-way regenerative repeater



May 31,1949. L. M. POTTS 2,471,891

TWO-WAY REGENERATIVE REPEATER ori inal Filed-oat. 19, 1942 I 3 Sheets-Shet 1 INVENTOR LOUIS M. POT'TS, DECEASED MARTHA W- C-fiTS, EXECUTRIX BY TORNEY May 31,1949. 1.. M. POTTS I 2,471,891

TWQ-WAY REGENE RATIVE REPEATER Original Filed 001. 19, 1942 s Sheets-Sheet 2 v INVENTOR LOUIS POTTS, DECEASED v MARTHA W. C. POTTS, EXECUTR'X W L LL L I n'roauev May 31, 1949. v L. M@ POTT S 2,471,891

TWO-WAY REGENERATIVE REPEA'IER Original Filed Oct. 19. 1942 3 sheets-Sheet 3 -|NVENTOR LOUIS M.POTTS, DECEASED MARTHA W.C.POTTS,EXEOUTRIX ATTORNEY Enciphered Si al, letters M M M M M Key SignalY M S M S M Original Signal R S M S M S The use of mechanically controlled and operated signalling arrangements have demonstrated advantages not obtainable in systems which are for the most part electrically controlled. Electrically controlled systems which usually include receiving and transmitting commutator distributors and relay controlled contact arrangements,

while advantageous for certain requirements, do not operate with the efficiency and comparatively slight maintenance afforded in mechanical systerns. A mechanical enciphering arrangement employing permutation code combinations with its attendant advantages over electrically controlled systems has thus far not been proposed. Mechanical enciphering systems are particularly desirable for the transmission of secret messages wherein it is advisable that signal distortion be kept to a minimum and that maintenance troubles do not delay communicating operations.

Accordingly the primary object of the present invention is the provision of a simple, reliable and practical system and apparatus for rendering messages unintelligible to unauthorized persons.

Another object of the invention is to provide a system and apparatus for precluding the unauthorized interception of messages by mechanical operations established in response to the respective control conditions.

A further object of the invention is the provision of a portable mechanically operated ciphering unit which may be readily associated with standard printing telegraph apparatus used for telegraphic communication.

A feature of this invention is the employment of directional s'witching means for automatically conditioning'a 'c'iphering unit for either enciphering or deciphering operations dependent upon the direction. of transmission.

An additional feature of the present invention is the provision of a mechanical enciphering unit in the form of a regenerative repeater.

Other features and advantages of the invention will appear as the description progresses and accordingly the invention should not be limited by the specific recitals appearing above.

The invention herein described utilizes a portable mechancial ciphering unit in the form of a regenerative repeater resembling the regenerative repeater illustratedin Patent No. 2,105,173 to W. J. Zenner et al. dated January 11, 1938. The unit includes a signal transmitting contact lever operable sequentially by aseries of selector bars in accordance with the joint control exercised over the bars by a series of levers which may be under the direct control of a key tape or in a modification of the invention under the control of a set of five code magnets and a single armature lever controlled by a selector magnet which may respond to either enciphered or deciphered signals. It is understood, of course, that other equivalent means of control may be employed.

The proposed construction includes a complete circuit system for operation of the unit which controls directional switching means for automatically enciphering or deciphering messages dependent on the direction of transmission. In one form of the invention a direction switch bar is employed which is operated either to one of two positions depending on the direction of the signals. The second form of directional switching employed features the use of a contact operating lever having a pair of transmitting contacts and a switching system which renders one or the other of the contacts efiective for transmission according to the direction of signalling.

All necessary equipment for the ciphering unit will be contained in a small portable receptacle that may be conveniently carried for use at locations having standard printing telegraph apparatus. A set of plugs are included with the unit to enable the unit to be quickly and easily associated with standard telegraph apparatus.

The invention may be more readily understood from the following detailed description and the drawings wherein:

Fig. 1 is a circuit diagram embodying the present invention,

Fig. 2 is a front elevational view of the structure according to the present invention; and

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2.

The present invention features the use of code magnets in place of the tape sensing levers employed in the first described embodiment of the invention and also the use of a transmitting con-- tact member having a pair of contact arms, only one of which is effective at a time dependent upon the direction of transmission.

Since in the instant embodiment of the in vention the tape sensing levers for shifting the code bars have been omitted, a second cam sleeve is unnecessary for the sensing and tape stepping functions. In this embodiment the direction switch bar has also been omittedand switching is now performed by means of a relay system.

Referring now to the drawings, 3313 represents a continually driven shaft. The release of a sleeve 34! is accomplished by a selector magnet 364 and clutch mechanism, except that the release of the sleeve 34! is accomplished solely by the selector magnet 364 in view of the fact that the start,

magnet has been dispensed with. Sleeve SM is released by the operation of gate latch 333 which acts upon the stop arm 342 integrally associated with the cam sleeve 34L Cam sleeve 34! carries a series of five transmitting cams 355i which are sequentially operable to control a series of five transmitting code bars 352. Cam sleeve as! also carries a start cam 353 for controlling the start bar 354, a cam 355 for controlling the stop bar 356 and a contact operating cam 35?, the purpose of which will hereinafter appear.

The code bars are controlled by a set of code magnets 36I which may be operated from a key tape transmitter 362 (Fig. 1) In response to signals from the key tape transmitter 362, armature levers 363 associated with respective code magnets 36! are moved to the left or right as viewed in Fig. 2 to enable their associated code bars 352 to assume similar positions. Similarly, selector magnet 364 positions the armature lever 366 to the left or right as pictured in the same view to cooperate with the notch 39!! in each code bar to enable the code bars to tilt 'to a counterclockwise or clockwise position. This tilting operation is provided by the operation of the transmitting code cams, which sequentially operateassociated T.-.shaped operating levers 399. -A Y-shapedi1ever...3 I 4 is. moved: to its marking or spacing position .under the combined influence of signals received.-by the selector magnet .3 64 and by the 'code..magnets 36 I ,..to operate the pair of contact;..arms 13I'Ito their marking. or spacing .positiom torcontrol the signal contact mechanism 318. @As indicated. in Fig. .1,..the contact mechanismii3l8 comprisesvtwo sets ofretransmitting or. repeater contacts 424 and 7446, .one set. being .associatdwith; each of the pairof arms -3I1. The contacts'426..are.effective when signals are incomingifrom la remote-station404 (Fig. .1) through ithe.bcipheringunit iflli to the local station"4i1l; and contacts- 445.. are effective when. signals areoutgoing'fromllocal station 40I through the iphering unit 400 to the remote station404. 'Just before the. end of each revolution of cam sleeve34I,--contact cam35! will move the bell crank lever 380 in a counterclockwise direction about its pivotlifil (as viewed in Fig.2) tooperate the make-before-break contaet382 for a purpose whichwill hereinafter appear, which position is maintainedduring the rest or stop period.

iIt-willbe understoodthat, as signals are rec'eived'bythe selector magnet 364, a startimpulse will precede each code combination to cause. the release ofthecam sleeve 34l. This causes the start cam353 to operate the start bar 354 for Sending a start-or no-current impulse by means of thecontact goperating'armall. Immediately thereafterythe-five code combination impulses will be transmitted under the control of the code bars *352 associated with their respective code bar*cams-35l. 'At thetermination of thetransmission' of the code combinations stop cam 355 operatesto position code bar 356 to' control-the contact operating arm 3I'I to its markingor' current position.

Referring now particularly to Fig. l, the circuit for operating the modified form of scrambling runit-will"be-described in detail. A local station '4fllfi is equipped with a combination keyboard transmitter'and' printer of any well-known type, whichvis designed to communicate by means-of central offices or exchanges 402 and- 403 with a 'Similarlyrequipped distant station: indicated at .404,'wwhich .is provided with a ciphering unit 405, identical: in? construction with the ciphering unit employed: in the modified form I of the invention.

Whenitis desired to attach the. cipheringunit to anmstandard telegraph printing station, plug and jack: connections may be made at- 4%, answer which-wil1: c0nnect..the local station 40! to 'a switch 408- and similarly connect the loopfrom the exchange 402 to the same SWitChfflt the plug connection-401. Whenswitch 408 is positionedl to its. .upyposition, I signals "may be transmitted edirectly fromstation wl to the central office 402 without any :enciphering operation taking place. However, .when it is desired to encipher: the signals,-the switch 4ll8 may be manually positioned to itsdownwardposition and for the. purposes of the present description, it will be presumed that the switch haswassumedlsuch a position. vIn-addition. the ciphering unit will be provided with a plug 409 which'may connect with any convenient ialternating current outlet to provide the currenttoa motor 4| I. The unit will be further equippedmwith. a rectifier indicated generally-(at 4 I 2. which. will provideopositive current over conductor.4l3, andnegative current over conductor 414, ..as ..is .well 1 known in rectifying circuits of this. type.

Q It will be presumed forthe first: portion of. the

.presentdescription, that the local station 4|! I telegraphy, over I .the I following circuit: From negative .lconductor --4I,4, over conductor 4I5,

through.selectorzmagnet 364, over conductor 4", through; tongue..4I8:;of. receiving relay 4I9 (now deeenergized) ,.over.conductor 42 I, and over con- .ductor;422ltopositive conductor 4I3. When the apparatus .atatheilocal station :40 I vis! in its. rest position, .wiriding42 3..of thedouble wound repeating re1ayiv424lis.energized. over the following ,cir- 'cuitz. From positiveconductor 4I3, over conductor.425,throughcontact 426,.over conductor 421.,

throughwiriding'.423l.of. relay 424, over conductor 428,Lthrol1ghtongue429 of switch 408 (now in "its down. position) over conductor 430, through the. printer apparatus at station 40 I, over conductor"432,'tongue 433 (in .its down position), and over. conductors .469 and M5, to the negative conductor4'l4.

"When, therefore. local station 443i transmits the start impulse, .the just described circuit is broken.at".the'itransmitting; contacts 410 at the local 'station 40I, inarwell-known manner, caus inglcontactl tongue. 43 I associated with the double wound relay '424. tobe released. When this occurs, the'f'ollowing circuits are established: From negative'f lead 4| 4, lover conductor 432, through relay433 (which now becomes energized), over conductor 434, through winding 435 of theldouble wound relay 419,:over conductor 436, through contact" tongue43l "(now released) of relay 424., and over. conductor 422 to tha positive. lead 4I3. Thus, atYthis-time bothrelay 433 and relay 4I9 become energized. When relay 4!!! becomes energized tonguellfl associated therewith is attracte'd and consequently thepreviously described circuit to "the selector magnet 334 is broken, causingthe release of Lthacam sleeve 34I for a cycle of operations,'.in amanner which iswellknown in start-stop, telegraphy. When relay 433 operates itilo'cks .up over the'following circuit, sinceas cam351 commences to rotate, the makebetoreebre'ak contact'"382.is permitted to operate to closetits. contact 384Jand open its contact 385 to, enable the establishment of the just-mentioned locking circuitof relay433: From positive conductor- 4I3, overconductor. 431, through contact 384 (now 'cl0sed),.over conductor-438, through tongue 439 of relayf433, through! the winding of relay=433 andover the'conductor 432 to the nega tive lead 4I 4. In addition the double Wound repeating relay44l is"-1ocked up .over the following 'circuitin order to. prevent the repetition of signals back into'the originating circuit when outgoing signals are being transmitted (sometimes calledecho suppression) lFrom negative potential (lead 4L4, throughlthe right-hand locking winding .of repeating relay 44I over conductor 443, through tongue444 of relay 44li (now closed), over conductorf445, over conductor 422,,to positive lead M3. .Sincatheiwinding 454 of repeating relay 44 I. islin. the. same. circuit with contacts 4463, and if.relayli44i was not thus locked-up, said relay wouldebecoperated in consonance with the vibrations l. of contact 446, thus operating its armaturee482. to disturb ..the. control .of selector magnet 364 .by :repeatingrelay 424. In a similar manner, the repeating relay- 424 will b locked .up in a .rcircuittto Joe describedilater, in order to prevent. the repeating trelay 424 from sending signals H back einto the. originating circuit while incoming signals are being received from a remote station.

At this time, contact 426 is rendered ineffective for transmission and conversely, contact 446 is conditioned for operation in the following manner: The afore-described energizing circuit for the double-Wound repeating relay 424 is provided with a shunt or by-pass to positive battery 443 at junction 426 on conductor 421, so that after the first start impulse has become effective, the contacts 426 will be shunted. This shunt circuit extends from junction 428 over armature 441 (when attracted as previously described), over conductors 445 and 422 to positive source 4l3. It is therefore found that when contact arms 3!1 move to their marking positions, the closure of contact 426 will be ineffective, so as not to interfere with the outgoing signals, inasmuch as the circuit to contacts 426 has now been shunted out of the transmitting circuit. Transmitting contact 446 is rendered effective for transmission at this time since its shunt circuit (hereinafter described) which is normally closed, is now opened, inasmuch as contact tongue 448 of relay 433 is attracted to open the shunt circuit for said transmitting contact so that signals may be repeated thereby to the distant station. Normally the shunt circuit for contact 446 is as follows: Over lead 455, through closed contact 448 of unoperated relay 433, and over lead or conductor 481.

It is assumed that signals from station 40! are being repeated by the repeating relay 424 which, by opening and closing its contacts 46! causes the signals to be repeated again by the energization and de-energization of the winding 435 of the double-wound relay 4!9. Therefore, selector magnet 364 will be similarly conditioned so that its armature lever 866 cooperates with the armature levers 863 of the code magnets 36! to control the Y-shaped transmitting lever M4. The central oflice 462 will transmit signals to station 464 as its loop circuit extends through the contact 446. Thus the loop circuit is conditioned to receive marking and spacing impulses according to the operation of the Y-shaped lever 3M. This circuit is as follows: From conductor 45!, through tongue 452 of switch 468, over the conductor 453, through the winding 454 of double-wound repeating relay 44! over conductor 455, to the contact 446, over conductor 456, through tongue 451 of switch 488 to the loop conductor 458 which leads to the central ofiice identified as 482. It will be understood that at the end of each cycle of operation the make-before-break contact 382 will operate to open the locking circuit extending over conductors 431 and 438 to the relay 433 so that the circuit will be returned to its normal condition.

The operation of cam 351 at the termination of each cycle of operation, through the operation of contact 382, causes the energization of stepping magnet 46! which steps the key tape at the key transmitter 362 to a new operating position. This circuit is as follows: From positive conductor M3, over conductor 431, through contact 385, over conductor 462 associated with cable 463, over conductor 464, through stepping magnet 46!, over conductor 465, over conductor 466, over conductors 461, 468, and 469, then over conductor M5 to the negative lead wire 4M. Therefore, during each cycle of operation stepping magnet 46! will operate to step the tape to a new position.

The code magnets 36! which are controlled by the key tape transmitter 362 are controlled by the now to be described circuit. From positive lead H3, over the conductor 41!, and over conductor 416 to the key tape bus bar 412, which is in this manner normally provided with positive potential. Thus, when a tape feeler in the tape transmitter 362 senses a perforation, a circuit will be established to its respective code magnets as follows: From positive bus bar 412, over the particular conductor 413 associated with the particular feeler pin, over conductor 413a, thence through the associated code magnet 36! to conductor 46? which acts as a negative bus bar over the following circuit: Over conductor 468, over conductor 468, and then over conductor M5 to negative lead 414. Therefore, according to the marking and spacing conditions of the key tape associated with the key transmitter 362 code magnets 413 will be energized under marking conditions and de-energized under spacing conditions.

The circuit will now be described in connection with the receipt of signals from the outlying or remote stations 484 which are enciphered by means of the ciphering unit 485 and then transmitted throgh central ofiices 483 and 482 to the local station 46!. At this time the circuit to the normally energized repeating relay 44!, which is similar to the normally energized repeating relay 424, is broken upon the receipt of a start or spacing impulse from the remote station 484. This initiates a cycle of operation by the release of cam sleeve 34!, as has been previously described in detail. The circuit extending to the repeating relay 44! is as follows: From source of potential at central ofiice 482, over conductor 458, through contact 451 of switch 488, over conductor 456, through contact 446, over conductor 455, through operating winding 454 of the double-wound repeating relay 44!, over conductor 453, through tongue 452 of switch 488, over conductor 45! to the other source potential at the central office 462. At this time, when the start impulse is transmitted from the remote station 464, relay 44! will become die-energized and its tongue 482 will be released to establish a circuit for relay H8 and relay 484 as follows: From positive lead 4l3, over conductor 422, through tongue 482 of repeating relay 44!, over conductor 485, through the winding 483 of relay 4l9, over conductor 486, through the winding of relay 484, over conductor to the negative lead 4l4. When relay 484- be comes energized, it is locked up as cam 351 operates to close the contact 384 as follows: From positive lead 413, over conductor 431, through contact 684, over conductor 438, through tongue 464, through the winding of relay 484, over conductor 432 to negative lead M4. Operation of relay 484 also causes the locking up of the repeating relay 424 to prevent this relay operating at this time in order that its contact tongue 43! may not interfere with signals in the circuit. This circuit is as follows: From positive lead 4|3, over conductor 422, over conductor 445, to contact tongue 482 of relay 484, over conductor 493, through the locking winding 484 of relay 424, over the conductor 495, and over the conductor 432 to the negativeconductor 4l4.

After the first start impulse has become efiec tive, transmitting contact 446 is bridged over the following shunt circuit already described above: Over conductor 455, through contact 448 of relay 433 (inasmuch as relay 433 is now de-energized), then over conductor 481. It is thus apparent at this time that the operation of contact 446 there after will produce no harmful result in the circuit in view of the shunt circuit provided therefor. Contact 426, however, is now free to operate, due to the fact that contact 441 of relay 433 is now open and the previously described circuit does not shunt out the contact 426.

Therefore, a circuit is made to repeat deciphered signals to the local printer 40! as follows: From positive lead M3, over conductor 425, through contact 426 (now operating), over conductor 427, through winding 423 of relay 424 (now locked) over conductor 428, through tongue 429 of switch 408, over conductor 433, through the printer at station 40!, and on a return path over conductor 432, through tongue 433, over conductor 469 and over conductor 415 to the negative source of potential 4M. It is further apparent at this time that selector magnet 364 will be operated according to incoming enciphered signals received from remote station 404 as relay 44! operates its tongue 482 and causes the operation of the double-wound repeatin relay M9, which by its contact tongue 4l8 repeats the incoming signals to the selector magnet 364. As has already been mentioned, when cam 35'! reaches its stop position the relay circuits are broken and the system is conditioned for reception in either direction.

contact means comprising a single signal receiving magnet and two repeating contacts controlled according to the signals received by said magnet, said contacts invariably operated in unison, one of said contacts invariably associated with one line section and the other of said contacts invariably associated with the other line section, a series of levers, one for each element of a code, said receiving magnet having its armature in operative relation to said levers, means to operate sid levers in timed relation to the corresponding elements of a signal received by said magnet, means to modify the motion of said levers according to the position of the armature when the lever is operated, means to operate said contact means by said levers to transmit a signal corresponding to the signal received by said magnet, and means controlled by signals received in one line section to place a shunt on the contact associated with that line section, whereby only one of said repeating contacts is effective at a time dependent upon the direction of transmission.

MARTHA W. C. POTTS, Erecutrix Under the Last Will and Testament of Louis M. Potts, Deceased.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,872,951 Hitt Aug. 23, 1932 2,073,266 Potts Mar. 9, 1937 

